Electric discharge tube



Patented Jan. 22, 1924.

. are STATES PATENT OFFICE.

GILLES HOLST, EKKO OOSTERHUIS, AND JOHANNES BRUIJNES, OF EINDHOVEN, NE'IH- ERLANDS, ASSIGNORS TO NAAMLOOZE VENNOOTSCHAP PHILIPS GLOEILAMPEN- FABRIEKEN, OF EINDHOVEN, NETHERLANDS.

, ELECTRIC DISCHARGE TUBE.

No Drawing.

To all whom it Be it known Oos'rnnnnrs,

may concern:

and JOHANNES BRU'IJNES, all subjects of the Queen of the Netherlands, residing at Eindhoven, in the Province of North Brabant, in the Kingdom of the Netherlands, have invented certain new and useful Improvements in or Relating to Electric Discharg Tubes, of which the followin is a specification.

his invention relates to electric discharge tubes in which a discharge is effected in a suitable gas-filling between electrodes which-at least at starting the tube-have Y a relatively low temperature such that they do not independently emit electrons.

In gas-filled electric discharge tubes of this kind it has always been difiicult to start the discharge without auxiliary devices, which enable the tube to be worked on the tension available on ordinary electric mains.

It is known to facilitate the starting of the discharge, by making the cathode of suitable material and by giving it a suitable construction. It has also been proposed to add a small proportion of non-rare gases or vapours to th gas-filling, but this has been chiefly for the purpose of counteracting the disintegration of the cathode and prolonging the life of the lamp. This latter result is obtained with various mixtures of gases without however lowering the starting potential. According to the present invention rare gases are added to a principal filling of rare gas for the purpose of reducing the starting potential of discharge tubes having independent discharge. An independent discharge is an electric discharge which is started simply by supplying a suitable alternating or direct current-tension to the electrodes without requiring cathode incandescence or any auxiliary device to liberate electrons or ions in the oath of the discharge such as characterize X-rays or ultraviolet ra s.

lhe conditions to be imposed on the composition of the gas-filling necessary to ensure the ignition of the tube on the tension Application filed June 1,

that we, GILLES HOLST, EKKo.

1922. Serial No. 565,230.

of ordinary electric mains have now been recognized and the invention relates to an electric discharge tube in which the starting potential is lowered by a special composition of the gas-filling. To that end the gas-filling of the tube consists principally of one gas and an added small quantity of another gas having an ionization potential lower than the tension at which the first inelastic collision in the first mentioned gas It has been found that when the gas-filling of the tube is composed as above described, discharge tubes of-any type may be started at ordinary electric main tensions independently of'the shape or nature of the electrodes.

It is quite likely that if the tube were filled exclusively with the gas used in this invention as an addition, all lectrons in the said gas would lose their ener in inelastic collisions before the ionization potential were reached, so that no discharge would take place. If however this gas is in but a small proportion in another gas the resonance potential of which is much higher, a large portion of the electrons has no opportunity of coming into resonance so that it can effect a discharge when the ionization potential is reached. For example, no discharge is produced either in neon or in argon at a tension of 220 volts in a tube in which the electrodes are about-5 cm. apart and the gas pressure is 1 cm. If however the tube is filled with neon to which 0.5 to 5% of argon is added, a discharge is produced at the same tension. The same result is obtained (even if the proportions of the mixture are altered) in mixtures of gases in which a small quantity of neon, argon or crypton is added to the principal volume of helium, or in which an addition of crypton is made to argon as the principal component.

The invention is applicable to gas-filled electric discharge tubes. of any type, that is tosay gas lam s or glow discharge lamps as well. as recti ers, amplifiers and the like.

What we claim is:

, g}, eemaa 1. A gas-filled electric discharge tube with 2. An electric discharge tube filled with independent discharge in which the gas-fillneon to which 0.5 t05% argon 15 added. 10 ing consists of a principal volume of one In testimony whereof we have afixed our rare gas and an added small quantity of ansignatures. other rare gas the ionization potential of V which is lower than the potential at which I GILLES HOLST. the first inelastic collision in the first men- EHO OOSTERHUIS. tioned gas occurs. JOHANNES BRUIJN ES. 

